Fehim Findik

• PhD
• Professor (Full) at Sakarya Applied Sciences University

The tribological properties such as surface hardness, friction and wear have been studied for AISI 316L stainless steel substrates which were co-ion implanted with zirconium and oxygen ions. It is found that the wear resistance for AISI 316L stainless steel substrates implanted with zirconium and oxygen ions increased quite a lot. It is concluded t...

Purpose The aim of the research is to increase piston and engine performance by using ceramic coated pistons instead of pistons which are manufactured from aluminum alloys and having a coated flame chamber. Design/methodology/approach Thermal torch and thermal shock tests were performed on the pistons and some specimens of 1.5 mm thick were prepar...

Purpose – The aim of the research is to investigate the ceramic brake lining on the brake performance.Design/methodology/approach – The brake lining which has new formulation has been produced by using various additive materials. Various techniques have been used in the production of brake lining. These ceramic linings were subjected to friction an...

A new methodology was developed to quantify tool wear during the die compaction process. The newly developed method is a non-destructive test using silicon rubber to transcript die surface profiles. Tool wear was measured by recording surface roughness of the cylindrical die molds on a surface profiler. To validate this procedure, an aluminum alloy...

Starting with elemental (pre-mixed) powders for producing shaped powder metallurgy alloys provides some advantages over a pre-alloyed system. The premixed powders are softer than prealloyed powders and therefore by using premixed powders it is possible to have higher compact densities and within a longer die life. In this research work, elemental a...

Sensors are one of the sensitive detection methods for sensing of micro/nano-sized structures. Sensors are simply systems that, by definition, detect changes in the environment and give warnings. The photosensitive sensors included in this group are outstanding for effective analysis. Photosensitive sensors are devices that absorb light in the UV-V...

Due to its properties such as high strength/weight ratio, enhanced corrosion resistance, low density, AA6061-T6 aluminum alloy welding is widely used in structural, automotive and rail industry. In this study, AA6061-T6 alloy was welded with robotic metal inert gas technique using ER5356 filler wire. The effects of different shielding gas compositi...

Carbon–carbon nanocomposites (CCNCs) are a material family consisting of carbon-based matrices reinforced with carbon (or graphite) fibers. CCNCs show variety from simple, one-way, fiber-reinforced structures to complex 3D woven structures. Composite contains two components, matrix and reinforcement. The reinforcing element can be either fiber, par...

Dye-sensitized solar cells (DSSCs) were first invented in 1991 by Gratzel and coworkers. The environmental friendliness, cost-efficient, and easy fabricate properties of these solar cell have attracted by the many researchers. Typically, DSSCs consist of four components: the photoanode consisting of a wide-bandgap semiconductor, the sensitizer acti...

Materials used for dental crowns show a wide range of variety, and a dentist's choice can depend on several factors such as patient desires, esthetics, tooth factors, etc. One of the most important issues for implant surgery is the primary stability and it should be provided to minimize the risks of screw loosening, failed osseointegration, or nonu...

This study provides a survey of the process in the improvement of carbon-based ZnO and TiO2-based nanocomposites such as graphene, graphene oxide, graphitic carbon nitride, [60]fullerenes, carbon nanotube, and tannin. Developments to increase photocatalytic efficiency of carbon-based ZnO and TiO2 photocatalysts have been examined in detail. The wor...

A new kind of functionally graded material (FGM) that mimics the inner porous structure and outer dense layer of human bone was produced using powder metallurgy. The inner part of the FGM material (16 mm in diameter) has porosity of approximately 60%, and its mechanical properties are compatible with cortical bone; however, the shell (1.8 mm in thi...

The selection of most proper materials in engineering design is known as an important stage of the design process. In order to successfully complete this stage, it is necessary to have sufficient knowledge about the structure of materials, density, melting point, thermal expansion coefficient, tensile and yield strength, elongation, modulus of elas...

A novel implant coating material containing graphene oxide (GO) and collagen (COL), and hydroxyapatite (HA) was fabricated with the aid of tannic acid by electrodeposition. The surface of Ti16Nb alloy was subjected to anodic oxidation, and then HA-GO coating was applied to Ti16Nb surface by the cathodic method. Then, COL was deposited on the surfac...

Buluş, damar içine yerleştirilen ve hemen sonrasında belli ölçüde genişletilerek damar içinde akışın gerektiği şekilde devamını sağlayan geçirgen, boruya benzer metal alaşımlı stent olup; biyoçözünür stentlerin üretimi için Fe-Mn-X-Y alaşımı içermesi, X' in Si, Co, Mo' den oluşan gruptan seçilen en az bir eleman içermesi, Y' nin ise C ve Pd?den olu...

To improve the properties of compact Ti alloys for biomedical applications, porous Ti-16Nb-10Zr-(0–15)Ta (wt.%) alloys were produced by the space-holding method using an ammonium hydrogen carbonate space holder. The pore size distribution, porosity ratio and mechanical properties of the obtained porous alloys were investigated. Also, the effect of...

In this study, the effect of Zr content on the corrosion resistance of Ti-16Nb alloy produced by powder injection molding was investigated. Electrochemical corrosion tests were carried out in simulated body fluid using electrochemical impedance spectroscopy and polarization curve analysis. It is observed that, with the addition of 10 wt.% Zr to the...

Ti-Nb-based alloys – with their superior mechanical properties and biocompatibility – are attractive biomaterials for orthopedic implants. By producing this alloys with a porous structure, it is possible to achieve mechanical properties similar to that of bone and to facilitate cellular activities. In this study, Ti16Nb (wt. %) alloys containing po...

The aim of this paper is to overview of surface preparation methods for titanium based on mechanical, thermal as well as chemical and electrochemical treatments on medical applications. Methods generally concerning deposition or addition of foreign materials. This paper highlights the common values behind the diverse approaches related to titanium...

Poroz yapılar, biyomedikal uygulamalarda implant ve kemik arasındaki mekanik uyumsuzluğu giderirler. Ayrıca, kemik dokunun porozite içine büyümesi ile implantın biyolojik sabitlenmesini sağlarlar. Bu çalışmanın amacı, belirli miktarda boşluk tutucu malzeme (NH4HCO3) içeriğinin Ti-16Nb alaşımının mikroyapı ve mekanik özelliklere olan etkisini incele...

zet Bu çalışmanın amacı Ta elementi ilavesinin, toz metalürjisi (TM) ile üretilmiş biyomedikal Ti-16Nb-10Zr alaşımının korozyon davranışına etkisini incelemektir. Optik mikroskop ve X-ışını kırınımı analizi (XRD) kullanılarak yapılan mikroyapı çalışmasına göre, Ti-16Nb-10Zr-(0-15)Ta alaşımları α+β fazlarından oluşmaktadır ve Ta içeriği artışı ile β...

Ti-Nb alloys are potential candidates owing to their excellent mechanical properties and high corrosion resistance for bioactive implant applications compared to other metallic materials. The purpose of this work is to investigate the effect of the Nb amount on the microstructure, mechanical properties, corrosion behavior and hydroxyapatite (HA) fo...

Stent, çeşitli nedenlerle engellenen damarlar için yapay bir koridor açmak, bu bölgede destek yapısı oluşturarak tıkanıklığı gidermek amacıyla kullanılan elemanlara verilen isimdir. Polimerik ve metalik içerikli biyo-uyumlu malzemelerin geliştirilmesi ve yaygınlaşması, stent uygulamalarındaki başarının artmasına neden olmaktadır. Günümüzde nitinold...

İnsan sert doku ( kemik gibi) biyo-implant malzemeleri için Ti-Nb esaslı alaşımlar biyo-uyumları, mekanik özellikleri, korozyon dirençleri gibi özellikleri açısından umut vadeden malzemelerdir. Bu çalışmada, Nb ilavesinin, Ti-Nb ikili alaşımının mikroyapı ve mekanik özellikleri üzerine etkisinin incelenmesi amacıyla saf Ti, Ti-16Nb, Ti-26Nb alaşıml...

Titanium and its alloys are used in production of implants such as knee and hip prostheses due to their superior properties. Ti–Nb–Zr ternary alloys are preferred over other metallic implant materials due to the presence of non-toxic elements, high corrosion resistance, good biocompatibility, and proper mechanical properties. The aim of this work i...

Ti-Ni and Ti-6Al-4V alloys commonly used in biomedical applications have disadvantages due to the mismatch of elastic modulus between the implant and the bones and presence of toxic elements (Ni, Al, and V). For this reason, in recent year's relatively low elastic modulus and non-toxic Ti-Nb based alloys have been developed. The purpose of this wor...

Aluminium-based powder metallurgy (PM) alloys have a number of advantages over cast and wrought aluminium alloys. These PM alloys can be produced using either prealloyed or elemental premixes, with the latter offering a longer die life because of their softer nature compared with prealloyed powders. It is found that the use of an Al-Cu premixed PM...

Ti alloys are the most remarkable group of biomedical implant materials because of their properties such as low elastic modulus, low density, super bio-compatibility, high strength/density ratio. Metastable β-Ti alloys have lower elastic modulus compared to other types so it is possible to reduce the biomechanical mismatch and stress shielding effe...

Toz metalurjisi (TM), üreticilere diğer imal usullerine göre büyük avantajlar sunan bir üretim yöntemidir. Bu yöntemin aşamaları olan toz üretimi, toz işleme, presleme, sinterleme ve sinterleme sonrası işlemlerdeki küçük farklılıklar nihai ürün özelliklerini büyük oranda etkilemektedir. Alüminyum alaşımları günümüzde en çok kullanılan ikinci mühend...

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Sintering and aging behaviours of Al–Cu–Mg powder metallurgy (PM) alloy produced from elemental powders were examined. After evaluating results from thermal analysis, tests were carried out on Al–4Cu alloys with magnesium contents of 0.5, 1 and 2 wt-% and it was found that additions of 1 wt-% Mg was most effective for enhancing the transverse ruptu...

Due to intense competition in automotive industry, new car models have to be launched as quickly as possible. A re-evaluation of the design and development phases has reshaped product development in order to get product earlier than competitors. Prototype production is one of the longest stages of product development due to physical verification ac...

In this study, ZnO nanoplates were synthesized rapidly via microwave assisted hydrothermal synthesis methods at relatively low temperatures and without any organic surfactants. The ZnO nanoplates were used as a dye sensitized photoanode. The vegetable tannins (Turkish valonea, sweet chestnut, mimosa and quebracho) and their Fe complexes were studie...

Havacılık alanında İnsansız Hava Araçlarına (İHA) yönelik talep ve çalışmalar tüm dünyada ve ülkemizde gün geçtikçe artmaktadır. İHA’lar, kumanda ya da uydu sistemleri aracılığıyla kontrol edilen, dikey olarak kalkış ve iniş yapabilen, uzun süreli uçuşları gerçekleştirebilen araçlardır. İHA’ların kullanım alanları arasında gözetleme, takip, nesne t...

To decrease the price of materials is very important. It is possible to make cost effective products by means of method that without machining i.e kitchen appliances, electronic devices and even plastic products. In this study one of the branch of design compression dies are investigated and a university emblem is studied using that kind of die. By...

In this study, the effect of aging heat treatment on fracture toughness and impact strength of Ni-625 superalloy fabricated by using powder injection molding (PIM) method was examined. After a feedstock was prepared by mixing the prealloyed Ni-625 superalloy powder, which was fabricated by gas atomisation, with a polymeric binder system and then it...

A green material suits most tunefully within ecosystem practices and donates to the achievement of a service- based economy. Due to the properties of non-toxic, organic and recycling, green materials are widely used in various industrial applications. Green materials can be categorized as natural materials, plastics, ceramics and composite material...

Wear is closely related to friction and lubrication; the study of these three subjects is known as tribology. In science and technology it is concerned with interacting surfaces in relative motion. Soft or hard film coating, alloying and composite structuring have all been developed to control wear and friction. This is achieved by improving materi...

Purpose – The purpose of the study was to find the best performance polymer material to be used in railway car bogies. Design/methodology/approach – Wear tests and optical and scanning electron microscopy were used. Findings – The friction coefficients of ultra-high-molecular-weight polyethylene (UHMWPE) and Nylon 6 polymers, as opposed to AISI 4...

In this study, the micro forcep of end-effector for robot surgery was produced by powder injection molding. The 17-4PH stainless steel powder and binder system based on a wax-polymer were mixed to fabricate the feedstock. The optimum solid loading (vol. %) was determined by the torque rheometer experiments. After injection molding, debinding and si...

Al2O3/SiC particulate reinforced metal matrix composites were produced by a stir casting process. The Al2O 3/SiC powder mix was prepared by reaction of aqueous solution of aluminium sulphate, ammonium sulphate and water containing SiC particles at 1200°C. 10 wt% of this hybrid ceramic powder with different sized SiC particles was added to a liquid...

Al2O3/SiC particulate reinforced metal matrix composites were produced by a stir casting process. The Al2O3/SiC powder mix was prepared by reaction of aqueous solution of aluminium sulphate, ammonium sulphate and water containing SiC particles at 1200 degrees C. 10 wt% of this hybrid ceramic powder with different sized SiC particles was added to a...

New developments in material science and its technologies find their best implementation areas in aircraft and space vehicles. Since the beginning of the powered flight, weight of airframes and systems are needed to be reduced. They are developed and built by light, durable and affordable materials through highly disciplined design, development, te...

Selection of proper materials for a diverse mechanism is one of the hardest tasks in the design and product improvements in various industrial applications. Materials play a vital and important function during the entire design and manufacturing process. The wrong selection of materials often leads to huge prices and ultimately results in product b...

In this study, PP and Talc/EPDM/PP composite materials are used. Foaming process is achieved by a conventional injection molding method. The influence of injection pressure and melting temperature on the average cell dimension, cell number, skin layer thickness, foam density and mechanical properties of investegated foam materials were evaluated. I...

This study concerns determination of optimum sintering and thermal process parameters for Ni-based alloy 625 superalloy formed by the method of powder injection molding (PIM). Samples, formed from the feedstock by mixing the prealloyed 625 powder with a multi-component binding system, are made subject to sintering at different temperatures followin...

Spinodal decomposition is regarded as small composition fluctuations over a large space, while a classical nucleation process is categorized by large composition fluctuations over a small space. Since the recent phases form the interface transversely by a permanent diffusional process with a steady alteration in composition, they must contain analo...

This study aims to determine optimum sintering and heat treatment parameters of powder injection moulded Nimonic-90 powder parts. Determination of optimum heat treatment conditions for sintered parts aimed to achieve maximum densities, and the microstructure and mechanical properties of the produced parts were characterised in sintered and heat tre...

Selection of appropriate materials for a distinct mechanism is one of the most difficult duties in the design and product developments in various industrial applications. Materials play a critical and significant role during the complete design and manufacturing process. Incorrect selection of materials frequently leads to enormous cost connection...

In this study, the use of nanocomposite polyethylene films to extend shelf life of food products and to enhance its barrier and mechanical properties was investigated. Nanocomposite was designated 80%wt LLDPE, 14.28%wt PE-g-MA, and 5.72%wt organoclay and package films were prepared on the “cast-film” line. The physical and chemical properties of th...

Selection and Implementation of ERP Systems: A Comparison of SAP implementation between BIH and Turkey In this research, the selection and implementation of ERP Systems will be discussed. The ERP concept, the selection process, and the importance of selecting a certain ERP solution for the companies will also be dealt with. However, implementation...

In this study, shoe manufacturing is analyzed and specific production policy is developed for the men’s shoe making company. The main characteristic of the shoe manufacturing is that the daily production rate and processing times are highly volatile and subject to high variances depending on the model and rapidly changing trends. The aim of this st...

This study aimed to determine optimum sintering parameters of IN718 superalloy powder parts which are shaped by the Powder Injection Moulding (PIM) method. At initial stage IN718 powder was mixed with a multi-component binder system. The resulting mixture was granulated and injected as standard tensile bar form. After moulding IN718 specimens were...

In the current work, 1wt% Acrawax was premixed with the aluminium and magnesium powder as a lubricant for the first group samples. However, no wax was used for the second group specimens. As a sintering aid, 1 wt% Mg was added for both group materials. Compaction of the specimens was performed using a manual Carver hydraulic press and a floating re...

An AISI 304 type of austenitic stainless steel and low carbon steel were cladded by explosive welding in this study. Four explosive loading rates were used with the range of 1 and 2.0. Stand-of distance (s=t) was also used as a welding parameter. Cladded materials have been subjected to heat treatment at 250°C for times of ranging from 1 to 4 h. Ef...

Purpose – The main goal of the present study is to investigate the friction and wear behaviors of aluminum matrix composites with an A360 matrix reinforced with SiC, B4C and SiC/B4C particles. Design/methodology/approach – Un‐reinforced aluminum casting alloy, Al/SiC, Al/B4C and Al/SiC/B4C aluminum composites were prepared for the present study. F...

Arc welding is a type of welding that uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The process of arc welding is widely used because of its low capital...

This paper reports the experimental findings on the development of the premixed elemental Al5Cu and Al5Cu0.5Mg powder metallurgy alloys. Aluminum powder was mixed with copper and magnesium powders in a macro- and a micro-level in order to produce light and strong Al-based powder metallurgy alloys using standard powder metallurgy processes. Differen...

Purpose This paper aims to research the tribological features of AISI 1035 steel, boronized at various parameters. Design/methodology/approach The samples were boronized via box boronizing method. By using Ekabor 2 powders, boronizing was conducted at 840, 880, 920, 960 and 1,000°C for two, four and six hours. Wear resistance of boronized samples...

Explosion welding (EXW) is one of the joining methods consisting of a solid state welding process in which controlled explosive detonation on the surface of a metal. During the collision, a high velocity jet is produced to remove away the impurities on the metal surfaces. Flyer plate collides with base plate resulting in a bonding at the interface...

A case study on the selection of materials for eye lenses is reported by means of Ashby's materials selection diagrams. In this study, 6 polymer materials of PMMA, PC, PS, PVC, PET, and PA are reviewed and their properties are found from the selection diagrams of Ashby and compared in a table. The final results confirmed that PMMA (acrylic) is the...

Steel, glass and polypropylene fiber reinforced concrete structures were investigated under repeated impact loads in this study. Twelve different concrete series prepared fiberless the one of all and the others reinforced polypropylene, glass, steel and hybrid fiber were produced. The polypropylene fibers in diameter of 50 mm, l/d (length/diameter)...

Purpose The purpose of this paper is to improve the wear resistance and tribological properties of magnesium and its alloys in order to apply them to the friction components. Design/methodology/approach Wear test, microhardness measurements, X‐ray diffraction (XRD), optical and electron microscopy examinations were applied. Findings The ceramic S...

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A new methodology was developed to observe and measure tool wear and tool surface quality during the die compaction process. The newly developed method is a non-destructive test that relies on silicon rubber to transcribe the inner surface profile of the compaction die. After verification of the method, aluminium and iron alloy powders were compact...

The tool life performance of multilayer hard coatings was evaluated for machining of spheroidal graphite cast iron. TiCN+TiC+Al2O3+TiN and TiCN+TiC+Al2O3+TiN multilayered coatings with different thick-nesses were fabricated on WC substrates using high temperature chemical vapor deposition (HTCVD). These cutting tools with hard multilayered coating...

In this study, tool life performance of multilayer hard coatings was evaluated for machining of nodular cast iron. With this regard, TiCN+TiC+TiCN+Al2O3+TiN and TiCN+TiC+TiCN+Al2O3+TiN multilayered coatings with different thicknesses were fabricated on WC substrates using high temperature chemical vapor deposition (HTCVD). These cutting tools with...

Bu çalışmada, toz metalurjisi üretim yöntemi kullanılarak makro ve mikro alaşımlama ile alüminyum metal toz malzemelerin sinterleme ve devamında ikincil işlemlerle mikro yapı kontrollünün gerçekleştirilmesi üzerine yapılan çalışmalar rapor edilmiştir. Yüksek safiyette element el tozlardan elde edilen Al5Cu ve Al5Cu0.5Mg alaşımları klasik toz metalu...

Purpose: The purpose of the work is to compare the physical and mechanical properties for argon atomized Al-1wt-%Mg powders with and without lubricant 1wt% Acrawac. Pure nitrogen sintering was performed and the effect of sintering atmosphere for the mixed Al-1%Mg powder compacts was investigated.Design/methodology/approach: One weight percent Acraw...

This paper presents the results of an experimental investigation on the effect of cutting speed in turning nodular cast iron with coated and uncoated cutting tools. Three different carbide cutting tools were used, namely TiCN+TiC+TiCN+Al2O3+TiN-coated carbide tools with multilayer coating of 7.5 and 10.5μm thickness and uncoated WC/Co tool. Turning...

Purpose The present study aims to find out the best polymer/polymer pair in electrical insulating applications. Moreover, the effects of different polymer counterpart and applied load on the friction and wear behaviour of PA 46 + 30%GFR and unfilled PA 66 thermoplastic polymers are to be studied. Design/methodology/approach Friction and wear tests...

In the present work, using a pad-on-disc-type wear tester, the tribological properties of the pad next to the disk made of cast iron were investigated with changing the substance of the components. As well, micro-structural characterisation of braking pads was performed using scanning electron microscopy and also temperature outcome of the pads was...

In this study, firstly a new wear testing machine was designed and produced in the university in order to investigate the wear behaviour of conventionally used sliding bearing alloys. Secondly, the wear tests of these bearings were performed by using this new machine. Three types of specimens’ wear behaviours were tested in this constructed machine...

Austempering is an isothermal heat treatment which when applied to ferrous materials, produces a structure that is stronger and tougher than comparable structures produced with conventional heat treatments. In this paper, ductile iron specimens were applied to various austempering temperatures and interpreted fatigue properties. In this test, Denis...

The aim of this work was to investigate the sintering, microstructure and mechanical properties of the premixed elemental Al5Cu and Al5Cu0.5Mg powder metallurgy (P/M) alloys for use in automotive bodywork applications. The correlation was set between the composition, sintering route, microstructure and properties of the sintered compacts. It was sh...

In this study, Ti–6Al–4V and Al plates were joined by explosive welding at various explosive loads. Tensile-shear, bending, hardness, microstructure and corrosion behaviours of the explosively joined samples were investigated. At the end of the tensile-shear tests carried out according to ASTM D 3165-95 standard, no seperation was observed in the i...

In recent years, a new class of ceramic foams with porosity levels up to 95% has been produced by the chemical method with aeration of a suspension containing foaming agents. The method of foamed suspensions has originated from the chemical reactions of water-soluble salts. In this study, sintered cellular ceramic composites with varying degrees of...

Purpose The aim of the research is to investigate wear performance of some phenolic composites with boric acid. Design/methodology/approach The brake lining which has new formulation has been produced by using various additive materials. Various techniques have been used in the production of brake lining. These phenolic composites were subjected t...

The mechanical behavior of aluminum alloys, prepared by mixing powder silicon, copper and magnesium in an appropriate amount with adequate amount of titanium and silicon carbide, exploring the compositions Al-14Si-4Cu-2Mg, Al-14Si-4Cu-2Mg-0.25Ti, Al-14Si-4Cu-2Mg-0.5Ti, Al-14Si-4Cu-2Mg- 10 SiC and Al-14Si-4Cu-2Mg-20 SiC was investigated by using uni...

In the present study, ceramic coated onto metals are applied by plasma-spraying technique. Three types of ceramic coating (Al2O3, Cr2O3, ZrO2) with and without bonding coating were applied to cast iron materials. The thermal torch and the thermal shock tests were conducted to coatings which were made according to the international standards. At the...

In this study, heat resistant carrying baskets’ microstructural and mechanical properties were investigated in order to increase the service life of them. By making some adjustments in alloying elements of these steels promising results were obtained. Heat resistant baskets used in heat treatment furnaces have approximately six or seven months serv...

Brake linings used in automotive disk brakes are usually made of various components such as phenolic resin, Cu powder, BaSO4, Al2O3, etc. In this study, 20 specimens with different compositions of the components were manufactured and a pad-on-disc-type wear tester was used. Friction and wear characteristics of the specimens next to a disk made of c...

In this study, bonding ability of copper and steel with explosion welding was investigated using different ratios of explosive and different stand-off distance. Experimental studies showed out that, copper and stainless steel could be bonded with a good quality of bonding properties with explosion welding. In the bonding interface, intermetallics w...